02485nas a2200241 4500008004100000022001400041245014800055210006900203260007700272300001400349490000600363520154400369653002901913653002801942653001501970653001201985653002201997100002402019700002402043700002802067700002302095856012502118 2013 eng d a1867-388000aIsolation, characterization, and identification of catalytically active species in the MoO3/SiO2 catalyst during solid acid catalyzed reactions0 aIsolation characterization and identification of catalytically a aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUN a1531-15370 v53 a

We report the isolation, characterization, and identification of the catalytically active species formed during various acid-catalyzed reactions if silica-supported MoO3 was used as a catalyst. We have reported previously the synthesis and extensive characterization of the silica-supported MoO3 catalyst prepared by the sol-gel process with ammonium heptamolybdate and ethyl silicate-40 as molybdenum and silica precursors, respectively. The TEM images showed uniformly distributed MoO3 nanoparticles on the high-surface area mesoporous silica support and high acidity (0.9mmolg-1) by using temperature-programmed desorption of ammonia (NH3-TPD) analysis. This catalyst has already shown high activity for various acid-catalyzed reactions. To understand the nature of catalytically active species formed during the reaction, the liquid-phase esterification of acetic acid and ethanol was studied as a probe reaction with very high acid conversion (83%) in 8h. During esterification, the reaction mixture turned blue, which indicated a change in the nature of the catalyst under reaction conditions. These catalytically active species formed in the reaction mixture were isolated and extensively characterized by using FTIR, Raman, powder XRD, BET surface area, NH3-TPD, energy dispersive X-ray, and TEM analysis. The characterization results revealed the insitu formation of silicomolybdic acid on the silica surface in the presence of water, which acts as catalytically active species responsible for the acid-catalyzed reactions.

10aesterification reactions10aheterogeneous catalysis10aMolybdenum10asilicon10asol-gel processes1 aKotbagi, Trupti, V.1 aBiradar, Ankush, V.1 aUmbarkar, Shubhangi, B.1 aDongare, Mohan, K. uhttps://library.ncl.res.in/content/isolation-characterization-and-identification-catalytically-active-species-moo3sio2-002299nas a2200253 4500008004100000022001400041245011800055210006900173260000800242300001400250490000600264520143200270653001201702653002801714653001801742653002401760653001401784100002301798700002401821700002301845700002001868700002801888856012901916 2014 eng d a1867-388000aPalladium nanoparticles supported on magnesium hydroxide fluorides: a selective catalyst for olefin hydrogenation0 aPalladium nanoparticles supported on magnesium hydroxide fluorid cNOV a3182-31910 v63 a

A one-pot synthesis of palladium nanoparticles supported on magnesium hydroxide fluoride has been performed with the fluorolytic sol-gel method. The prepared catalysts were characterized by using various physicochemical techniques. The sol-gel method led to high surface area (>135 m(2)g(-1)), mesoporous catalysts (pore volume=0.19-0.23 cm(3)g(-1), pore diameter=3-5 nm) with uniformly dispersed palladium nanoparticles approximately 2 nm in diameter on the surface. The catalysts synthesized by using different concentrations of aqueous hydrofluoric acid exhibited changing surface and acidic properties. Very high dispersion of palladium on magnesium fluoride (47%) was obtained with 1 wt% palladium loading. The catalysts were used for hydrogenation of various olefins in the presence of other organic functionalities at room temperature and atmospheric hydrogen pressure. Various substituted olefins were hydrogenated with almost 100% conversion and selectivity. The catalysts were recycled efficiently over five cycles without appreciable loss in catalytic activity. There was no palladium leaching under the reaction conditions, which was confirmed by inductively coupled plasma atomic emission spectroscopy analysis. Activation of olefin on the catalyst surface could not be observed by in situ FTIR studies, indicating facile activation of hydrogen on the palladium supported on magnesium hydroxide fluoride.

10aalkenes10aheterogeneous catalysis10aHydrogenation10amagnesium fluorides10aPalladium1 aAcham, Vaibhav, R.1 aBiradar, Ankush, V.1 aDongare, Mohan, K.1 aKemnitz, Erhard1 aUmbarkar, Shubhangi, B. uhttps://library.ncl.res.in/content/palladium-nanoparticles-supported-magnesium-hydroxide-fluorides-selective-catalyst-olefin01796nas a2200253 4500008004100000022001400041245013300055210006900188260000800257300001200265490000600277520091200283653002401195653001601219653002801235653002701263653000901290100002401299700002801323700002301351700001701374700002401391856012701415 2017 eng d a2168-048500aEnvironmentally benign bioderived carbon microspheres-supported molybdena nanoparticles as catalyst for the epoxidation reaction0 aEnvironmentally benign bioderived carbon microspheressupported m cJAN a904-9100 v53 a

A one pot synthesis of molybdenum oxide nanoparticles (NPs supported on bioderived carbon microspheres is reported. The catalyst was synthesized by the low temperature hydrothermal (LTH) method using D-glucose and bagasse as the carbon source. The carbonization of bagasse resulted in the formation of nonuniform carbon microspheres while glucose resulted in uniform carbon spheres. SEM and STEM elemental mapping show the uniform distribution of molybdenum oxide NPs over the carbon microspheres. XPS spectroscopy confirmed that molybdenum was in the Mo6+ oxidation state. The 1% MoO3 supported on carbon microspheres derived from D-glucose showed excellent catalytic activity up to 100% olefin conversion with 100% epoxide selectivity using organic tent-butyl hydroperoxide as an oxidant. The catalyst was successfully used for up to five cycles without losing substantial activity and selectivity.

10aCarbon microspheres10aepoxidation10aheterogeneous catalysis10aHydrothermal synthesis10aTBHP1 aDoke, Dhananjay, S.1 aUmbarkar, Shubhangi, B.1 aGawande, Manoj, B.1 aZbori, Radek1 aBiradar, Ankush, V. uhttps://library.ncl.res.in/content/environmentally-benign-bioderived-carbon-microspheres-supported-molybdena-nanoparticles